Add nosetests setup.cfg.
Try using cashew to test pytest filter.
Make pytest filter use --stop and --verbose flags.
Add more debugging info to integration test.
List parsers explicitly in wrapper. Fix env parsing in custom names.

Currently all registered parsers were being used all the time, in a
random order. However, parsers need to be run in order since environment
parsers need to have run before we create documents. So, make parsers an
explcit list which allows ordering as well as selection of which
parseres to use.

Fix up output-name processing so it handles environment variables and
correctly handles leading slashes.
Fix usage of NullHandler()
Add back warning if no config files found. Fix tests.